The Mercedes-Benz 230SL uses a P21W bulb size for both front and rear turn signal applications. The replacement chart covers vehicle production spanning 1963 to 1967.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W is the sole bulb type specified for the Mercedes-Benz 230SL across both front and rear turn signal positions for the 1963-1967 model years.
The P21W is a single-filament bulb, meaning it serves one lighting function only, which is consistent with its dedicated use in turn signal applications rather than combined stop/tail positions.
The P21W operates at 12 volts and draws 21 watts, placing it in the standard signalling power range defined by ECE regulations.
The bulb uses a BA15s bayonet base, where "BA" denotes a bayonet cap fitting, "15" refers to the 15mm base width, and the lowercase "s" indicates a single contact at the base, corresponding to the single-filament design.
The P21W is governed by ECE standards, a regulatory framework recognized across Europe and numerous other markets worldwide, which defines its electrical and photometric requirements.
The front and rear turn signal positions on the 230SL share an identical bulb specification across all listed model years, indicating no positional differentiation in bulb type was required by the manufacturer.
Because the BA15s base carries a single contact, it is not interchangeable with the BA15d base, which carries two contacts and is found on dual-filament bulbs such as the P21/5W.